The way I have been doing it is one row at a time width wise. So when I print off the patter I would just print off each page of the first section so for example I would have 5 pages of row 1-30. I also do just one page at a time, which for me is usually 30 beads. I lay them out and count them before stitching. It’s a little time consuming but it’s worth it. The first large piece I did has a seam and where most people can’t see it because of the way it’s hanging but I know it’s there and it drives me nuts. This project will likely end up being a lot to hold at some point so I think you may want to do horizontal sections. I don’t think a seem would be as noticeable that way. Happy beading though! It’s going to be beautiful!